Two days ago I got a Hornby R763 ex-Caledonian single (currently in LMS marron). It runs very well. The cab roof is bent in one corner and one of the steps is broken off and missing, but I don't mind. I also don't own the box or the certificate, but I know it's one of 5100 made, even though this one was made in 1983, the tooling for everything is reused from the 1963 model.
The magic of the GWR